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 Prime magic (Posted on 2018-09-29)
What is the smallest possible constant of a 3×3 magic square containing nine distinct non-composite numbers only?

 No Solution Yet Submitted by Ady TZIDON No Rating

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 re: solution(?) | Comment 3 of 4 |
(In reply to solution(?) by Justin)

Right - I just modified my program to find all the minimum constants (zeros) for a,b,c <21. There are two solutions (discounting rotations and reflections)

Here they are below.
I also verified Justin's complete solutions:  min constant = 111 for non-neg terms a,b,c (-50, 50) and the constant = 177 as the minimum for strictly primes for a, b, c all between -1000,1000. (I found only 1 solution + rotations etc. in each case, once again, those he gave.)

That being said, I have no idea how to prove this is a minimum for all a,b,c.

0

2     -7      5

3      0     -3

-5      7     -2

0

2     -5      3

1      0     -1

-3      5     -2

Edited on September 29, 2018, 8:22 pm
 Posted by Steven Lord on 2018-09-29 16:19:50

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